Tube piercing machine



April 8, 1958 i w. -LDE GAIN 2,829,983

TUBE PIERCING MACHINE 'Filed March so, 195s 2 s sheets-sheet 1 L FIGA l,

/82 :ha i/@1b April 8, 195.8 W, J, DE GAIN 2,829,983

TUBE PIERCING MACHINE 23N ATTORNEY April 8, 1958 w. J. DE GAIN TUBE PIERCING MACHINE 3 Sheets-Sheet 3 Filed March 30, 1956 FIG- 4 INVENTOR. WILLIAM J. DEGAIN- w A ATTORNEY United States PatentO TUBE PIERCING MACHINE William I. De Gain, Detroit, Mich., assignor to Koppy Tool and Die Company, Ferndale, Mich., a corporation of Michigan l Application March so, 1956, serial N 575,080

12 Claims. (Cl. 164-108) This invention relates to tube piercing machines and more particularly to an automatic head unit for piercing round or irregular shaped holes in tubes. Y

Heretofore, in piercing tubing, since the mandril must be small enough to accept the tube freely, the piercing action causes the surface of the mandril to Contact the tube in one direction only. With no support against force necessary to fracture the metal, the mandril pushes away from the direction of the cut causing misaligntnent of punch and die and collapse of the tube around the hole.

In order to overcome this diiiiculty, it is the primary object of the present invention that the tube be compressed into the shape of an ellipse through the medium of an upper and lower compression block, thus forcing the tube into contact with the mandril at the opposite surfaces of the mandril. With this condition, the pierc` ing action can now take place without causing misalignment of punch and' die or causing collapse of the tube. This will result in a more efficient punching operation and a better nished punched opening.

It is the further object of the present invention to provide an automatic head unit, which enables the aforementioned sequences to be performed with a single power supply such as an air, air hydraulic,` or hydraulic or other type of hydraulic impact cylinder. l

It is the further object of the present invention to provide an upper and a lower compression block, which together with the use of springs, or other cushions, is adapted to position the tube and mandril so that the tubeV contacts the mandril on its opposite sides and in the direction of the punching action. This is accomplished by utilizing the driving power of the cylinder through the medium of a pair of tie rods.

It is the further object of the present invention to effect this initial compression function of the tube with respect to the mandril before the punch actually contacts the tube after which the piercing is completed, and the unit operation reverses causing the punch to strip itself from the tube and the compression blocks to release in opposite directions and allowing the free removal of the tube from the mandril.

It is the still further object of the presentinvention to provide a pair of oppositely arranged compression blocks, each of which carries upon its inner surfacera removable and interchangeablebloch insert with a recess which is substantially semi-circular in cross section to receive the corresponding halves of the tube to be punched.

It is the still further object of the present invention to provide these inserts recessed slightly undersized with respect to Vthe vertical axis of the tube punched and of a radius slightly greater than the transverse radius of the particular tube to be punched. The purpose of this is that the initial engagement of the insert withv the upper and lower portions of the tube to be punched will cause an initial compression of the said tube vertically or at least in the direction of the proposed punching operaice tion in order that the tube will snugly and tightly engage surfaces of the mandril over which it is positioned.

It is the still further object to incorporate in the present invention mechanism whereby the power transmitted from the hydraulic cylinder or other motor to the said compression blocks will be exactly equal so that an equal amount of pressure is exerted upon both sides of the tube and at the inserts.

These and other objects Will be seen in the following specification and claims in conjunction with the appended drawings, in which:

Figure 1 is a fragmentary vertical section of the present tube piercing machine, partially broken away for illustration.

Figure 2 is a section taken on line 2-2 of Figure l.

Figure 3 is a fragmentary section taken on line 3 3 of Figure 1.

Figure 4 is a front fragmentary perspective view of the present tube piercing machine, differing only in minor detail from the illustrations in Figuresrl, 2, and 3.

It will be understood that the above drawings illustrate merely a preferred embodiment of the invention and that other embodiments are contemplated within the scope of the claims hereafter set forth.

Referring to the drawings herein the present tube piercing machine includes, the preferably upright base block plate 11, which is fragmentarily shown and which would normally be incorporated in some standard or other base for securing the same rigidly in the upright position shown. Figure 2 shows a transverse aperture 12 through plate 11 and through which loosely extends the mandril 13 over which the particular tube T is loosely projected for the punching operation hereafter described.

As shown in Figure 2, the mandril 13 at the end thereof behind plate 11 is suitably secured within collar V14, and this collar is secured as at 15 to the body bracket 16 carried upon the back of plate 11 and suitably secured thereto as by the fasteners 17.

As thus shown in Figure 3, the front at face of plate 11 includes the depressed at upright surface 18 which terminates in the opposed upright sidewalls 19 against which bear the wear plates 20. A pair of upright opposed gibs 21 are mounted upon the outer surface of plate 11 and project inwardly over the plane surface 18 and are suitably secured to plate 11 as by the fasteners 22 shown in Figure 4.

The lower compression block 24 is positioned upon plate 11 forwardly of the surface 18 and includes a pair of laterally projecting slide members 25 which bear against the wear plates 20 and which are slidably retained under and with respect to the gibs 21, to thereby retain the said compression block against outward movement with respect to plate 11. Key 23, Figures 1 and 2, is nested partly within slot 23" in plate 11 for the purpose of limiting downward movement of block 24. Key 23 of Fig. 4 corresponds to this key 23.

The two tie rods 26 shown in Figure l, have lower portions 27 of reduced diameter which extend through the compression block 24, and which are suitably secured thereto as by the nuts 28 and the interposed washers 29.

These tie rods 26, also have portions of reduced diam' cylindrical shank 3.5, depends from cylinder head 33, and

centrally through the cylinder ram 31, and its lower threaded portion 36, receives the securing nut 37, by which the said cylinder is immovably securedwith respect to the cylinder ram. 4

As is conventional, said cylinder includes a reciprocal piston, and depending therefrom the piston rod`3t, which slidably projects through the shank 35. The lower end of the piston rod 38, is suitably securedto the punch retainer piston ram 40, through which is threaded titting 44 which extends down into the central aperture 43 in ram 40. The opposite end of the fitting is joined to the piston rod as at 45, a suitable lock nut 46, beingr ernployed.

Slide projections 25 extend from opposite ends of ram 40 and underlie the gibs 21. Ram 40 has a pair of transverse apertures there-through into which are snugly projected the bushings 41 which slidably-receive tie rods 26. Ram 40 has a central, flat, depressed surface portion 44' against which registers the lock nut 46 in the assembly by which thepiston rod 38 is joined to ram 413.

Plate 4S is positioned and secured upon the under surface of ram 40 and depending therefrom is the punch mounting and securing sleeve 49, which supportably retains the cylindrical shank 50 of the depending punch 51 as shown in Figure l. In Figure l punch 51 is shown in the position it would assume immediately after the fracture of the tube.

There is also-provided an upper compression block 52, of a construction similar to lower compression block 24, and which also has a pair of laterally projecting guides 53 which underlie portions of the gibs 21. Bushings S4 are also projected through the upper compression block 52 in order to slidably receive the tie rods 26.

Enlarged upright bores 55 are formed in the upper compression block 52 adjacent tie rods 26, and are adapted to cooperatively and loosely receive the coil springs 56 which loosely surround the tie rods 26. The respective opposite ends ofV said springs are adapted to be cooperatively engaged by the enlarged heads 47 at the respective ends of bushing 41 and 54, 'd

As shown in Figures land 2, the base mount plate 11 has formed therein a pair of transverse slots within which areV immovably secured a pair of keys 58. Primarily, these keys are adapted to limit the upward movement of the upper compressionblockSZ. At the same time, the keys are also adapted to limit the downward movement of ram 40 should this become necessary. In normal operation, however, it is contemplated that the ram will stop before it engages with the said keys S, as shown in Figure 1, because at this point, there will be eiected an automatic reversal of the uid pressure connection to the fittings 39 in cy1indcr^34, and thus etiect an automatic withdrawal of the piston rod 38 and the ram 40 secured thereto.

The upper surface of the top compression block 52 has a central recess 59 into which loosely projects the punch mounting sleeve 49 as in Figure l.

Additional slots are formed transversely in the mount plate 11 within which are secured a pair of additional keys 60. These keys lie in the path of vertical move-v ment of the two compression blocks 52 and 24 and are so arranged as to positively limit the vertical movement of the two compression blocks towards each other in order that they will be properly centered with respect'to the mandril 13. Y Y e v The under surface of the upper compressionblock is undercut Yor recessed in order to snugly'receive therein insert block 61, whoselower'surface 62, is substantially.- in the form ofv a semi-circle and which .is adapted to cooperatively register with theupper half of the tube as shown. A corresponding recess is also preformed within the upper portion ofthe lower compression block 24 which -is adapted to snugly and retainably Vreceive, the

lower insert 63. This insert has formed transversely of its upper surface a semi-circular groove 64 adapted to cooperatively receive the lower one-half of the tube being punched.

In operation, it is contemplated the opposing substantially semi-circular surfaces 62 and 64 to be each slightly less than a complete semi-circle and of a radius slightly greater than Vthe radius of the tube T to be punched. The reason for this is that in the initial operation of the punching machine, the two inserts will be brought together compressively against opposite sides of the tube but there will still be a slight spaced relation between the two inserts due to the fact that the arcuate surfaces 62 and 64 each portend less than 18() degrees. Further compression of the said inserts as they are brought together will cause the initial desired compression of the tube T into the form of an ellipse, so that its upper and iower surfaces will snugly engage corresponding surfaces of mandril 13. At this point, the relative inward movements of the two inserts is, of course, limited by the keys 60. This assures there will be proper centering of the said inserts with respect to the tube T to be punched.

In Figure l, there is shown a suitable die 65, properly nested and secured within mandril 13. The mandril directly below the die is transversely apertured at 66 and is in communication with a corresponding aperture 67 in insert 63. This aperture is in alignment with an addit tion-al depending aperture 68 formed in the lower compression block 24, whereby the slug removed during the punching operation is free to escape down through the slot 68' found in the key 23, which is adapted to limit the downward movement of the lower compression block 24.

As best seen in Figure l, there are provided a pair of upright plates 69 whose lower inwardly directed end portions are suitably secured with respect to undercut portions of the upper compression block 52 as by the fasteners 70 for movement in unison. As shown in Figure l,

` the elongated plates 69 extend along the sides of the upper compression block 52 and at their upper ends have inward projections 71 adapted to be engaged by the punch ram 40 when it has been returned to its upper and inoperative position on reversal of the fluid connections to i the motor 34, all in the manner hereafter described. The

position shown.

upward return movement of ram 40 as it engages the plates 69, will effect a slight upward releasing movement of the upper Compression block 52 for disengaging the same from the tube after the punching operation. The reaction of the cylinder 34 to the upward return movement of piston rod 38 transmits through tie rods 26 corresponding downward movement of the lower compression block 24 in the manner hereafter described for disengaging said block and its insert from the tube T after the punching operation, and to permit withdrawal of the punched tube from the mandril 13.

There is shown in Figure 4 a front perspective view o one embodiment of the present tube piercing machine which is substantially in accordance with the drawings in Figures l, 2 and 3. Though there are a few slight changes, the purpose of this view is to present a more realistic appearance to the punching machine and also to show the inactive position of the punch. Each of the parts shown in Figure 4 correspond substantially to the parts shown in Figures 1, 2 and 3. The identification of the said parts is carried over in Figure 4 by priming of the corresponding numerical designation.

In the illustration shown in Figure 4, the base mount plate 11', is supported in an upright position and secured by clamps 73 to the upright opposed plates 72. Those connect with plate 16 which corresponds to the bracket 16 on Figure 2 by which themandril 13 is mounted in Operation Normally, the punching machine is in theoperative positionl shown inV Figure 4, with the punch '5P-withdrawn. Initially, a suitable tube` to be punchedyisslidably and loosely projected over mandril V13' andtakes the position shown in Figure 2 for illustration.r It is contemplated in this connection that depending upon the desired location of the punched opening with respect to the length of the tube suitable means would be employed for limiting the inward projection of the tube on the mandril so as to obtain the correct location.

As the initial operation of the punching machine iuid source of pressure which, in the present case, may be compressed air, is established to the upper fitting 39 of the pneumatic cylinder` 34 of Figure l. This causes an initial downward movement of piston rod 38 and the punch retainer piston ram 40 secured thereto effecting a corresponding downward movement of punch 51.

This initial downward movement of ram 40 brings the same into engagement with the coil springs 56 which are gradually compressed and a minimum force of approximately 500 pounds per square inch for example is transmitted through the said springs to the upper compression block 52 causing this block and its insert 61 to operatively and compressively engage the upper one-half of the tube T to be punched.

In view of the fact, that the cylinder 34 is in effect free floating just as soon as pressure is transmitted by the ram 40 to the springs 56, there will be a reaction upwardly of the said cylinder 34. This reaction is transmitted through the cylinder ram 31 to the tie rods 26 and in turn ya corresponding upward movement of equal force is transmitted to the lower compression block 24, to effect an upwardmovement thereof and its tube engaging insert 63. Y

Accordingly, in the initial operation of the punching machine, there will be an initial compression of the tube T by the two inserts 61 and 63 and this compression will be, of course,'equal. The initial compression, accordingly, effects a slight ellipsing vertically of the tube which was previously loosely mountedv over the mandril 13. This ellipsing will bring opposing interior portions of the tube into tight operative contact with top and bottom wall portions of the mandril 13. Now the tube T is ready for the subsequent punching operation. Up to this point, the punch 51 is still out of contact with the tube T.

The keys 60 have, in the meantime, served their function of limiting the respective movement of the top and bottom compression blocks to the central position indicated in Figure l.

Thereafter, continued downward movement of piston rod 33 will accordingly effect downward movement of punch 51 until it engages the surface of the tube. Thereafter, the pressure, of course, will build up sufficiently until the said punch in cooperation with die 65 effects a fracture of the tube. The relative position of the parts just after fracture is shown in Figure 1. At this point, there will be an automatic reversal of the fluid Yconnection, so that pressure fluid will be delivered to the lower fitting 39 of cylinder 34 to thus effect an immediate withdrawal of piston rod 33 and a corresponding withdrawal of punch 51.

As the ram 4i) is withdrawn to the inoperative position shown in Figure 4, the upper surface of said ram engages projection 71 on the tube plates 69, thus effecting a slight upward movement thereof. As the lower ends of these plates are secured to the upper compression block 52. it is seen that there will be a slight upward movement produced of the said compression block which will be limited by engagement of said block in its upper surface with the keys 53. Movement is sufficient to permit easy withdrawal of the tube that is, however, once the lower compression block has been withdrawn.

Just as soon as there is an upward movement of the piston rod 3S, there will be a reaction of cylinder 34 in the opposite direction. This reaction is transmitted through ram 31 and tie rods 26'and tothe lower compression block 24, thus effecting a corresponding slight downward movement of the said lower compression block until it engages the stop key 23. Now the tube has been disengaged and is free to be withdrawn manually or automatically.

At this point, it must be remembered that care has to be taken that the tube is not ellipsed beyond its plastic limits. It must be able to assume its initial roundness after the compression blocks are released or returned to the initial position shown in Figure 4.

Thus the cycle has been completed and the machine is ready for the next punching operation.

On the preferred embodiment, the present punching unit is provided with a single base mount plate 11. It is contemplated that there could be an adjustable radial mount carried upon a sliding base which would permit both radial and longitudinal adjustment of the punching mechanism, as desired, and for a particular job. v

The cycle includes initial compression of the tube with respect to the mandril after which the punch operatively engages the tube for the punching operation after which there is an automatic reversal of the punch in orderto strip itself from the tube and this is followed by an automatic release -of the compression blocks to thus allow the free removal of the tube from the mandril.

The slug from the operation is now free to fall into the apertures 66, 67, 68 and 68 shown in Figure l.

In this connection, it will be noted that to prevent the slug from obstructing the passage of a new tube into position, the lower compression block, in the preferred embodiment travels only one and a half times the wall thickness of the tube. This will prevent the slug from positioning between the compression block and the mandril, without being wipedv away whenever another tube is pushed onto the mandril.

With the use of an adjustable mount, the present punching unit can be mounted in multiple tandem if desired and be made suitable to receive parts which are mechanically handled through automation, and are easily readjusted to product changes by readjusting, the position of the unit and altering the mandril to suit.

Having described my invention, reference should now be had to the claims which follow.

l claim:

1. In a tube piercing machine, an upright mounting plate, a mandril projecting loosely through said plate normally thereof adapted to loosely receive the tube to be punched, means supporting said mandril rearwardly of the plate, upper and lower tube compression blocks slidably mounted on Said plate on opposite sides of the mandril, their inner opposing surfaces being semi-cylindrically slotted to cooperatively and compressively engage said tube against opposing surfaces of the mandril, a cylinder ram spaced from said blocks, tie rods extending slidably through the upper compression block and secured at their respective opposite ends to said ram and the lower compression block, a cylinder mounted on said ram including a reciprocal piston rod extending through the ram, a punch ram slidably mounted on said plate and tie rods and joined to said piston rod, a punch depending from said latter ram, aligned with the mandril axis and adapted for operative shearing registry with a die in said mandril, yielding compression means mounted loosely on said tie rods bearing upon the upper compression block, said punch ram on downward movement adapted to operatively engage said compression means exerting a downward force on said upper compression block, the reaction of the cylinder transmitting through the cylinder ram and the tie rods a corresponding equal upward force upon the lower compression block, upright return means joined to said upper compression block for movement therewith, and including an abutment normally in the path of return movement of the punch ram and engageable thereby on reverse movement of the piston rod, producing an upward tube-releasing force on the upper compression block, the reaction of said cylinder transmitting through said tie rods a corresponding downward tube-releasing force on said lower compression block.

2. The tube piercing machine of claim 1, the slots in said compression blocks being of slightly greater radii than the radius of the tube and each slot portending an arc less than 180 degrees, whereby contact of'said blocks with each other partially ellipses the tube tightly against opposing walls of the mandril.

3. The tube piercing machine of claim 1, and a key secured on said mounting plate interposed between the paths of movement of said compression blocks forlimit ing the relative movement of said blocks toward each other.

4. The tube piercing machine of claim l, and keys secured on said mounting plate respectively above and below the upper and lower compression blocks in their respective paths of movement away from each other for limiting their separating movements.

5. The tube piercing machine of claim 1, and keys secured on said mounting plate respectively above and below the upper and lower compression blocks in their respective paths of movement away from each other for limiting their separating movements, said keys being spaced from said blocks a distance approximately 1/2 times the wall thickness of the tube punched.

6. The tube piercing machine of claim 1, and keys secured on said mounting plate respectively above and below the upper and lower compression blocks in their respective paths of movement away from each other for limiting their separating movements, the key above said upper compression block lying in the path of downward movement of said punch ram.

7. The tube piercing machine of claim l, and headed bushings secured respectively in said upper compression block and punch ram receiving the tie rods, with their heads in opposed relation, said compression means consisting of coiled springs whose opposite ends are operatively engaged by the heads of said bushings.

e assegna 8. The tube piercing machine'of claim 1, upper portions of said upper compression block having enlarged recesses concentric with said tie rods, said compression means consisting of vcoiled springs with their lower ends loosely nested within said recesses.

9. The tube piercing machine of claim 1, opposing surfaces of said compression blocks having recesses therein of rectangular cross section, and insert blocks of similar cross section tightly nested within said recesses, said semicylindrically shaped slots being formed in the inserts.

l0. The tube piercing machine of claim 1, the mounting of said cylinder including a cylinder head, a central shank projecting down through said cylinder ram slidably receiving said piston rod, and a nut threaded on said shank engaging said ram.

ll. The tube piercing machine of claim 1, said tie rods having portions of reduced diameter adjacent their opposite ends for retaining engagement respectively with said cylinderrarn and lower compression block, and nuts threaded on the opposite ends of said tie rods retainingly engaging said cylinder ram and the compression block respectively.

12. The tube piercing machine of claim l, said mounting plate having a at depressed surface which opposing inner side walls, guide anges at the base of said punch ram and compression blocks projecting from opposite sides thereof for slidingk movement relative to said side walls', and a pair of spaced hold down gibs secured on said mounting plate with inner portions thereof overlying and slidably and retainingly engaging said ianges.

References Cited in the file of this patent UNITED STATES PATENTS 814,200 Gibson Mar. 6, 1906 '2,202,894 Y Bihler June 4, 1940 2,326,536 Harstock et al Aug. 19, 1943 2,354,860 Harstock et al Aug. 1, 1944 2,632,511 Hamilton Mar. 24, 1953 2,670,795 Griep Mar. 2, 1954 

1. IN A TUBE PIERCING MACHINE, AN UPRIGHT MOUNTING PLATE, A MANDRIL PROJECTING LOOSELY THROUGH SAID PLATE NORMALLY THEREOF ADAPTED TO LOOSELY RECEIVE THE TUBE TO BE PUNCHED, MEANS SUPPORTING SAID MANDRIL REARWARDLY OF THE PLATE, UPPER AND LOWER TUBE COMPRESSION BLOCKS SLIDABLY MOUNTED ON SAID PLATE ON OPPOSITE SIDES OF THE MANDRIL, THEIR IONNER OPPOSING SURFACES BEING SEMI-CYLINDRICALLY SLOTTED TO COOPERATIVELY AND COMPRESSIVELY ENGAGE SAID TUBE AGAINST OPPOSING SURFACES OF THE MANDRIL, A CYLINDER RAM SPACED FROM SAID BLOCKS, TIE RODS EXTENDING SLIDABLY THROUGH THE UPPER COMPRESSION BLOCK AND SECURED AT THEIR RESPECTIVE OPPOSITE ENDS TO SAID RAM AND THE LOWER COMPRESSION BLOCK, A CYLINDER MOUNTED ON SAID RAM INCLUDING A RECIPROCAL PISTON ROD EXTENDING THROUGH THE RAM, A PUNCH RAM SLIDABLY MOUNTED ON SAID PLATE AND TIE RODS AND JOINED TO SAID PISTON ROD, A PUNCH DEPENDING FROM SAID LATTER RAM, ALIGNED WITH THE MANDRIL AXIS AND ADAPTED FOR OPERATIVE SHEARING REGISTRY WITH A 